Various gauge means for checking the accuracy of a keyway cut in a shaft are known in the art. The devices as known in the art, however, are not capable of measuring the perpendicularity of the keyway side walls to the centerline of the keyway. The devices as known are capable of only measuring the centering and/or parallelism of a shaft keyway. In order to check for the perpendicularity of the keyway side walls, separate time consuming measurements are required unless an instrument having a key cut to size to fit within the keyway is utilized. Such an instrument results in added cost of the cutting and measuring operation since the device is suitable for use with only one size keyway.
For example, the use of a horizontal indicator dial and probe in conjunction with a micrometer is currently available on the market through the company A.u.W. Busch GmbH and Company. This device, however, does not contain any means for measuring the perpendicularity of a keyway side wall to the centerline of the keyway.
U.S. Pat. No. 2,494,152 describes a tool for checking the centrality and alignment of a keyway in a shaft. The tool utilizes a stationary block which is set in the keyway followed by an adjustment of the tool utilizing a separate leveling device. To determine if the keyway is in alignment and properly centered, the tool is removed from the keyway and repositioned at the opposite end of the keyway and opposite side of the shaft to see if the level of the keyway remains the same. If the level is not the same, the shaft is misaligned and non-centered. The separate leveling device is the only indicator of the amount of the inaccuracy present.
U.S. Pat. No. 2,611,187 describes a gauge for measuring the misalignment of a shaft keyway which includes the use of a dial to indicate the amount the keyway is off. The structure of the gauge utilized is complex in nature and is not capable of measuring the perpendicularity of the shaft side walls.
U.S. Pat. No. 2,556,761 describes a tool combination including a micrometer caliper and a dial gauge. The dial gauge functions to give plus or minus readings without resetting the caliper. The micrometer caliper is utilized to measure the outside diameter and the mean dimension of a shaft, however, and is not disclosed for measuring a keyway.
U.S. Pat. No. 3,457,650 describes a keyway gauge used for aligning a tool which will cut a keyway and for checking the accuracy of the cut. A micrometer or dial gauge can be utilized to set the initial position of the gauge to provide for an accurate cut.
Accordingly, the art does not describe a device which is capable of measuring the perpendicularity of keyway side walls to the centerline of a shaft keyway either alone or in combination with a means of measuring the centering and parallelism of a keyway shaft.